From mboxrd@z Thu Jan  1 00:00:00 1970
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [PATCH 03/13] writeback: per-task rate limit on
 balance_dirty_pages()
Date: Wed, 24 Nov 2010 11:23:07 +0100
Message-ID: <1290594187.2072.440.camel@laptop>
References: <20101117042720.033773013@intel.com>
	 <20101117042849.650810571@intel.com>
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Cc: Andrew Morton <akpm@linux-foundation.org>, Jan Kara <jack@suse.cz>,
 Christoph Hellwig <hch@lst.de>, Dave Chinner <david@fromorbit.com>,
 Theodore Ts'o <tytso@mit.edu>,  Chris Mason <chris.mason@oracle.com>, Mel
 Gorman <mel@csn.ul.ie>, Rik van Riel <riel@redhat.com>, KOSAKI Motohiro
 <kosaki.motohiro@jp.fujitsu.com>, linux-mm <linux-mm@kvack.org>,
 linux-fsdevel@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>
To: Wu Fengguang <fengguang.wu@intel.com>
Return-path: <owner-linux-mm@kvack.org>
In-Reply-To: <20101117042849.650810571@intel.com>
Sender: owner-linux-mm@kvack.org
List-Id: linux-fsdevel.vger.kernel.org

On Wed, 2010-11-17 at 12:27 +0800, Wu Fengguang wrote:
> +       if (unlikely(current->nr_dirtied >=3D current->nr_dirtied_pause |=
|
> +                    bdi->dirty_exceeded)) {
> +               balance_dirty_pages(mapping, current->nr_dirtied);
> +               current->nr_dirtied =3D 0;
>         }=20

Was it a conscious choice to use
  current->nr_dirtied =3D 0
over=20
  current->nr_dirtied -=3D current->nr_dirtied_pause
?

The former will cause a drift in pause times due to truncation of the
excess.

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